It is known to provide a plastic jacket around the core of wire ropes such as disclosed, for example, in U.S. Pat. No. 3,705,489 granted Dec. 12, 1972. The primary function of such jacket is to prevent metal to metal contact between the core and the outer strands wound on the core and also to space away the outer strands by forcing the outer strands into the jacket. Another function of the jacket is to prevent escape of the lubricant that is normally placed in the core to decrease the friction between the components of the core and thus increase the life of the wire rope.
In the manufacture of large diameter cable, it became very difficult to adequately compress the outer rope strands into a thick core plastic jacket so as to displace jacket material into the voids formed between the strands and the core so as to space the outer strands. Because of this, the large diameter wire ropes were made slightly oversize but, when the outer strands became fully embedded into the core jacket during the first hours of operation, they tended to loop out.